fs/btrfs/delayed-ref.c

   1 /*
   2  * Copyright (C) 2009 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/sched.h>
  20 #include <linux/slab.h>
  21 #include <linux/sort.h>
  22 #include "ctree.h"
  23 #include "delayed-ref.h"
  24 #include "transaction.h"
  25
  26 struct kmem_cache *btrfs_delayed_ref_head_cachep;
  27 struct kmem_cache *btrfs_delayed_tree_ref_cachep;
  28 struct kmem_cache *btrfs_delayed_data_ref_cachep;
  29 struct kmem_cache *btrfs_delayed_extent_op_cachep;
  30 /*
  31  * delayed back reference update tracking.  For subvolume trees
  32  * we queue up extent allocations and backref maintenance for
  33  * delayed processing.   This avoids deep call chains where we
  34  * add extents in the middle of btrfs_search_slot, and it allows
  35  * us to buffer up frequently modified backrefs in an rb tree instead
  36  * of hammering updates on the extent allocation tree.
  37  */
  38
  39 /*
  40  * compare two delayed tree backrefs with same bytenr and type
  41  */
  42 static int comp_tree_refs(struct btrfs_delayed_tree_ref *ref2,
  43                           struct btrfs_delayed_tree_ref *ref1, int type)
  44 {
  45         if (type == BTRFS_TREE_BLOCK_REF_KEY) {
  46                 if (ref1->root < ref2->root)
  47                         return -1;
  48                 if (ref1->root > ref2->root)
  49                         return 1;
  50         } else {
  51                 if (ref1->parent < ref2->parent)
  52                         return -1;
  53                 if (ref1->parent > ref2->parent)
  54                         return 1;
  55         }
  56         return 0;
  57 }
  58
  59 /*
  60  * compare two delayed data backrefs with same bytenr and type
  61  */
  62 static int comp_data_refs(struct btrfs_delayed_data_ref *ref2,
  63                           struct btrfs_delayed_data_ref *ref1)
  64 {
  65         if (ref1->node.type == BTRFS_EXTENT_DATA_REF_KEY) {
  66                 if (ref1->root < ref2->root)
  67                         return -1;
  68                 if (ref1->root > ref2->root)
  69                         return 1;
  70                 if (ref1->objectid < ref2->objectid)
  71                         return -1;
  72                 if (ref1->objectid > ref2->objectid)
  73                         return 1;
  74                 if (ref1->offset < ref2->offset)
  75                         return -1;
  76                 if (ref1->offset > ref2->offset)
  77                         return 1;
  78         } else {
  79                 if (ref1->parent < ref2->parent)
  80                         return -1;
  81                 if (ref1->parent > ref2->parent)
  82                         return 1;
  83         }
  84         return 0;
  85 }
  86
  87 /*
  88  * entries in the rb tree are ordered by the byte number of the extent,
  89  * type of the delayed backrefs and content of delayed backrefs.
  90  */
  91 static int comp_entry(struct btrfs_delayed_ref_node *ref2,
  92                       struct btrfs_delayed_ref_node *ref1,
  93                       bool compare_seq)
  94 {
  95         if (ref1->bytenr < ref2->bytenr)
  96                 return -1;
  97         if (ref1->bytenr > ref2->bytenr)
  98                 return 1;
  99         if (ref1->is_head && ref2->is_head)
 100                 return 0;
 101         if (ref2->is_head)
 102                 return -1;
 103         if (ref1->is_head)
 104                 return 1;
 105         if (ref1->type < ref2->type)
 106                 return -1;
 107         if (ref1->type > ref2->type)
 108                 return 1;
 109         /* merging of sequenced refs is not allowed */
 110         if (compare_seq) {
 111                 if (ref1->seq < ref2->seq)
 112                         return -1;
 113                 if (ref1->seq > ref2->seq)
 114                         return 1;
 115         }
 116         if (ref1->type == BTRFS_TREE_BLOCK_REF_KEY ||
 117             ref1->type == BTRFS_SHARED_BLOCK_REF_KEY) {
 118                 return comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref2),
 119                                       btrfs_delayed_node_to_tree_ref(ref1),
 120                                       ref1->type);
 121         } else if (ref1->type == BTRFS_EXTENT_DATA_REF_KEY ||
 122                    ref1->type == BTRFS_SHARED_DATA_REF_KEY) {
 123                 return comp_data_refs(btrfs_delayed_node_to_data_ref(ref2),
 124                                       btrfs_delayed_node_to_data_ref(ref1));
 125         }
 126         BUG();
 127         return 0;
 128 }
 129
 130 /*
 131  * insert a new ref into the rbtree.  This returns any existing refs
 132  * for the same (bytenr,parent) tuple, or NULL if the new node was properly
 133  * inserted.
 134  */
 135 static struct btrfs_delayed_ref_node *tree_insert(struct rb_root *root,
 136                                                   struct rb_node *node)
 137 {
 138         struct rb_node **p = &root->rb_node;
 139         struct rb_node *parent_node = NULL;
 140         struct btrfs_delayed_ref_node *entry;
 141         struct btrfs_delayed_ref_node *ins;
 142         int cmp;
 143
 144         ins = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
 145         while (*p) {
 146                 parent_node = *p;
 147                 entry = rb_entry(parent_node, struct btrfs_delayed_ref_node,
 148                                  rb_node);
 149
 150                 cmp = comp_entry(entry, ins, 1);
 151                 if (cmp < 0)
 152                         p = &(*p)->rb_left;
 153                 else if (cmp > 0)
 154                         p = &(*p)->rb_right;
 155                 else
 156                         return entry;
 157         }
 158
 159         rb_link_node(node, parent_node, p);
 160         rb_insert_color(node, root);
 161         return NULL;
 162 }
 163
 164 /* insert a new ref to head ref rbtree */
 165 static struct btrfs_delayed_ref_head *htree_insert(struct rb_root *root,
 166                                                    struct rb_node *node)
 167 {
 168         struct rb_node **p = &root->rb_node;
 169         struct rb_node *parent_node = NULL;
 170         struct btrfs_delayed_ref_head *entry;
 171         struct btrfs_delayed_ref_head *ins;
 172         u64 bytenr;
 173
 174         ins = rb_entry(node, struct btrfs_delayed_ref_head, href_node);
 175         bytenr = ins->node.bytenr;
 176         while (*p) {
 177                 parent_node = *p;
 178                 entry = rb_entry(parent_node, struct btrfs_delayed_ref_head,
 179                                  href_node);
 180
 181                 if (bytenr < entry->node.bytenr)
 182                         p = &(*p)->rb_left;
 183                 else if (bytenr > entry->node.bytenr)
 184                         p = &(*p)->rb_right;
 185                 else
 186                         return entry;
 187         }
 188
 189         rb_link_node(node, parent_node, p);
 190         rb_insert_color(node, root);
 191         return NULL;
 192 }
 193
 194 /*
 195  * find an head entry based on bytenr. This returns the delayed ref
 196  * head if it was able to find one, or NULL if nothing was in that spot.
 197  * If return_bigger is given, the next bigger entry is returned if no exact
 198  * match is found.
 199  */
 200 static struct btrfs_delayed_ref_head *
 201 find_ref_head(struct rb_root *root, u64 bytenr,
 202               struct btrfs_delayed_ref_head **last, int return_bigger)
 203 {
 204         struct rb_node *n;
 205         struct btrfs_delayed_ref_head *entry;
 206         int cmp = 0;
 207
 208 again:
 209         n = root->rb_node;
 210         entry = NULL;
 211         while (n) {
 212                 entry = rb_entry(n, struct btrfs_delayed_ref_head, href_node);
 213                 if (last)
 214                         *last = entry;
 215
 216                 if (bytenr < entry->node.bytenr)
 217                         cmp = -1;
 218                 else if (bytenr > entry->node.bytenr)
 219                         cmp = 1;
 220                 else
 221                         cmp = 0;
 222
 223                 if (cmp < 0)
 224                         n = n->rb_left;
 225                 else if (cmp > 0)
 226                         n = n->rb_right;
 227                 else
 228                         return entry;
 229         }
 230         if (entry && return_bigger) {
 231                 if (cmp > 0) {
 232                         n = rb_next(&entry->href_node);
 233                         if (!n)
 234                                 n = rb_first(root);
 235                         entry = rb_entry(n, struct btrfs_delayed_ref_head,
 236                                          href_node);
 237                         bytenr = entry->node.bytenr;
 238                         return_bigger = 0;
 239                         goto again;
 240                 }
 241                 return entry;
 242         }
 243         return NULL;
 244 }
 245
 246 int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
 247                            struct btrfs_delayed_ref_head *head)
 248 {
 249         struct btrfs_delayed_ref_root *delayed_refs;
 250
 251         delayed_refs = &trans->transaction->delayed_refs;
 252         assert_spin_locked(&delayed_refs->lock);
 253         if (mutex_trylock(&head->mutex))
 254                 return 0;
 255
 256         atomic_inc(&head->node.refs);
 257         spin_unlock(&delayed_refs->lock);
 258
 259         mutex_lock(&head->mutex);
 260         spin_lock(&delayed_refs->lock);
 261         if (!head->node.in_tree) {
 262                 mutex_unlock(&head->mutex);
 263                 btrfs_put_delayed_ref(&head->node);
 264                 return -EAGAIN;
 265         }
 266         btrfs_put_delayed_ref(&head->node);
 267         return 0;
 268 }
 269
 270 static inline void drop_delayed_ref(struct btrfs_trans_handle *trans,
 271                                     struct btrfs_delayed_ref_root *delayed_refs,
 272                                     struct btrfs_delayed_ref_node *ref)
 273 {
 274         rb_erase(&ref->rb_node, &delayed_refs->root);
 275         if (btrfs_delayed_ref_is_head(ref)) {
 276                 struct btrfs_delayed_ref_head *head;
 277
 278                 head = btrfs_delayed_node_to_head(ref);
 279                 rb_erase(&head->href_node, &delayed_refs->href_root);
 280         }
 281         ref->in_tree = 0;
 282         btrfs_put_delayed_ref(ref);
 283         delayed_refs->num_entries--;
 284         if (trans->delayed_ref_updates)
 285                 trans->delayed_ref_updates--;
 286 }
 287
 288 static int merge_ref(struct btrfs_trans_handle *trans,
 289                      struct btrfs_delayed_ref_root *delayed_refs,
 290                      struct btrfs_delayed_ref_node *ref, u64 seq)
 291 {
 292         struct rb_node *node;
 293         int merged = 0;
 294         int mod = 0;
 295         int done = 0;
 296
 297         node = rb_prev(&ref->rb_node);
 298         while (node) {
 299                 struct btrfs_delayed_ref_node *next;
 300
 301                 next = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
 302                 node = rb_prev(node);
 303                 if (next->bytenr != ref->bytenr)
 304                         break;
 305                 if (seq && next->seq >= seq)
 306                         break;
 307                 if (comp_entry(ref, next, 0))
 308                         continue;
 309
 310                 if (ref->action == next->action) {
 311                         mod = next->ref_mod;
 312                 } else {
 313                         if (ref->ref_mod < next->ref_mod) {
 314                                 struct btrfs_delayed_ref_node *tmp;
 315
 316                                 tmp = ref;
 317                                 ref = next;
 318                                 next = tmp;
 319                                 done = 1;
 320                         }
 321                         mod = -next->ref_mod;
 322                 }
 323
 324                 merged++;
 325                 drop_delayed_ref(trans, delayed_refs, next);
 326                 ref->ref_mod += mod;
 327                 if (ref->ref_mod == 0) {
 328                         drop_delayed_ref(trans, delayed_refs, ref);
 329                         break;
 330                 } else {
 331                         /*
 332                          * You can't have multiples of the same ref on a tree
 333                          * block.
 334                          */
 335                         WARN_ON(ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
 336                                 ref->type == BTRFS_SHARED_BLOCK_REF_KEY);
 337                 }
 338
 339                 if (done)
 340                         break;
 341                 node = rb_prev(&ref->rb_node);
 342         }
 343
 344         return merged;
 345 }
 346
 347 void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
 348                               struct btrfs_fs_info *fs_info,
 349                               struct btrfs_delayed_ref_root *delayed_refs,
 350                               struct btrfs_delayed_ref_head *head)
 351 {
 352         struct rb_node *node;
 353         u64 seq = 0;
 354
 355         /*
 356          * We don't have too much refs to merge in the case of delayed data
 357          * refs.
 358          */
 359         if (head->is_data)
 360                 return;
 361
 362         spin_lock(&fs_info->tree_mod_seq_lock);
 363         if (!list_empty(&fs_info->tree_mod_seq_list)) {
 364                 struct seq_list *elem;
 365
 366                 elem = list_first_entry(&fs_info->tree_mod_seq_list,
 367                                         struct seq_list, list);
 368                 seq = elem->seq;
 369         }
 370         spin_unlock(&fs_info->tree_mod_seq_lock);
 371
 372         node = rb_prev(&head->node.rb_node);
 373         while (node) {
 374                 struct btrfs_delayed_ref_node *ref;
 375
 376                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
 377                                rb_node);
 378                 if (ref->bytenr != head->node.bytenr)
 379                         break;
 380
 381                 /* We can't merge refs that are outside of our seq count */
 382                 if (seq && ref->seq >= seq)
 383                         break;
 384                 if (merge_ref(trans, delayed_refs, ref, seq))
 385                         node = rb_prev(&head->node.rb_node);
 386                 else
 387                         node = rb_prev(node);
 388         }
 389 }
 390
 391 int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
 392                             struct btrfs_delayed_ref_root *delayed_refs,
 393                             u64 seq)
 394 {
 395         struct seq_list *elem;
 396         int ret = 0;
 397
 398         spin_lock(&fs_info->tree_mod_seq_lock);
 399         if (!list_empty(&fs_info->tree_mod_seq_list)) {
 400                 elem = list_first_entry(&fs_info->tree_mod_seq_list,
 401                                         struct seq_list, list);
 402                 if (seq >= elem->seq) {
 403                         pr_debug("holding back delayed_ref %#x.%x, lowest is %#x.%x (%p)\n",
 404                                  (u32)(seq >> 32), (u32)seq,
 405                                  (u32)(elem->seq >> 32), (u32)elem->seq,
 406                                  delayed_refs);
 407                         ret = 1;
 408                 }
 409         }
 410
 411         spin_unlock(&fs_info->tree_mod_seq_lock);
 412         return ret;
 413 }
 414
 415 int btrfs_find_ref_cluster(struct btrfs_trans_handle *trans,
 416                            struct list_head *cluster, u64 start)
 417 {
 418         int count = 0;
 419         struct btrfs_delayed_ref_root *delayed_refs;
 420         struct rb_node *node;
 421         struct btrfs_delayed_ref_head *head = NULL;
 422
 423         delayed_refs = &trans->transaction->delayed_refs;
 424         node = rb_first(&delayed_refs->href_root);
 425
 426         if (start) {
 427                 find_ref_head(&delayed_refs->href_root, start + 1, &head, 1);
 428                 if (head)
 429                         node = &head->href_node;
 430         }
 431 again:
 432         while (node && count < 32) {
 433                 head = rb_entry(node, struct btrfs_delayed_ref_head, href_node);
 434                 if (list_empty(&head->cluster)) {
 435                         list_add_tail(&head->cluster, cluster);
 436                         delayed_refs->run_delayed_start =
 437                                 head->node.bytenr;
 438                         count++;
 439
 440                         WARN_ON(delayed_refs->num_heads_ready == 0);
 441                         delayed_refs->num_heads_ready--;
 442                 } else if (count) {
 443                         /* the goal of the clustering is to find extents
 444                          * that are likely to end up in the same extent
 445                          * leaf on disk.  So, we don't want them spread
 446                          * all over the tree.  Stop now if we've hit
 447                          * a head that was already in use
 448                          */
 449                         break;
 450                 }
 451                 node = rb_next(node);
 452         }
 453         if (count) {
 454                 return 0;
 455         } else if (start) {
 456                 /*
 457                  * we've gone to the end of the rbtree without finding any
 458                  * clusters.  start from the beginning and try again
 459                  */
 460                 start = 0;
 461                 node = rb_first(&delayed_refs->href_root);
 462                 goto again;
 463         }
 464         return 1;
 465 }
 466
 467 void btrfs_release_ref_cluster(struct list_head *cluster)
 468 {
 469         struct list_head *pos, *q;
 470
 471         list_for_each_safe(pos, q, cluster)
 472                 list_del_init(pos);
 473 }
 474
 475 /*
 476  * helper function to update an extent delayed ref in the
 477  * rbtree.  existing and update must both have the same
 478  * bytenr and parent
 479  *
 480  * This may free existing if the update cancels out whatever
 481  * operation it was doing.
 482  */
 483 static noinline void
 484 update_existing_ref(struct btrfs_trans_handle *trans,
 485                     struct btrfs_delayed_ref_root *delayed_refs,
 486                     struct btrfs_delayed_ref_node *existing,
 487                     struct btrfs_delayed_ref_node *update)
 488 {
 489         if (update->action != existing->action) {
 490                 /*
 491                  * this is effectively undoing either an add or a
 492                  * drop.  We decrement the ref_mod, and if it goes
 493                  * down to zero we just delete the entry without
 494                  * every changing the extent allocation tree.
 495                  */
 496                 existing->ref_mod--;
 497                 if (existing->ref_mod == 0)
 498                         drop_delayed_ref(trans, delayed_refs, existing);
 499                 else
 500                         WARN_ON(existing->type == BTRFS_TREE_BLOCK_REF_KEY ||
 501                                 existing->type == BTRFS_SHARED_BLOCK_REF_KEY);
 502         } else {
 503                 WARN_ON(existing->type == BTRFS_TREE_BLOCK_REF_KEY ||
 504                         existing->type == BTRFS_SHARED_BLOCK_REF_KEY);
 505                 /*
 506                  * the action on the existing ref matches
 507                  * the action on the ref we're trying to add.
 508                  * Bump the ref_mod by one so the backref that
 509                  * is eventually added/removed has the correct
 510                  * reference count
 511                  */
 512                 existing->ref_mod += update->ref_mod;
 513         }
 514 }
 515
 516 /*
 517  * helper function to update the accounting in the head ref
 518  * existing and update must have the same bytenr
 519  */
 520 static noinline void
 521 update_existing_head_ref(struct btrfs_delayed_ref_node *existing,
 522                          struct btrfs_delayed_ref_node *update)
 523 {
 524         struct btrfs_delayed_ref_head *existing_ref;
 525         struct btrfs_delayed_ref_head *ref;
 526
 527         existing_ref = btrfs_delayed_node_to_head(existing);
 528         ref = btrfs_delayed_node_to_head(update);
 529         BUG_ON(existing_ref->is_data != ref->is_data);
 530
 531         if (ref->must_insert_reserved) {
 532                 /* if the extent was freed and then
 533                  * reallocated before the delayed ref
 534                  * entries were processed, we can end up
 535                  * with an existing head ref without
 536                  * the must_insert_reserved flag set.
 537                  * Set it again here
 538                  */
 539                 existing_ref->must_insert_reserved = ref->must_insert_reserved;
 540
 541                 /*
 542                  * update the num_bytes so we make sure the accounting
 543                  * is done correctly
 544                  */
 545                 existing->num_bytes = update->num_bytes;
 546
 547         }
 548
 549         if (ref->extent_op) {
 550                 if (!existing_ref->extent_op) {
 551                         existing_ref->extent_op = ref->extent_op;
 552                 } else {
 553                         if (ref->extent_op->update_key) {
 554                                 memcpy(&existing_ref->extent_op->key,
 555                                        &ref->extent_op->key,
 556                                        sizeof(ref->extent_op->key));
 557                                 existing_ref->extent_op->update_key = 1;
 558                         }
 559                         if (ref->extent_op->update_flags) {
 560                                 existing_ref->extent_op->flags_to_set |=
 561                                         ref->extent_op->flags_to_set;
 562                                 existing_ref->extent_op->update_flags = 1;
 563                         }
 564                         btrfs_free_delayed_extent_op(ref->extent_op);
 565                 }
 566         }
 567         /*
 568          * update the reference mod on the head to reflect this new operation
 569          */
 570         existing->ref_mod += update->ref_mod;
 571 }
 572
 573 /*
 574  * helper function to actually insert a head node into the rbtree.
 575  * this does all the dirty work in terms of maintaining the correct
 576  * overall modification count.
 577  */
 578 static noinline void add_delayed_ref_head(struct btrfs_fs_info *fs_info,
 579                                         struct btrfs_trans_handle *trans,
 580                                         struct btrfs_delayed_ref_node *ref,
 581                                         u64 bytenr, u64 num_bytes,
 582                                         int action, int is_data)
 583 {
 584         struct btrfs_delayed_ref_node *existing;
 585         struct btrfs_delayed_ref_head *head_ref = NULL;
 586         struct btrfs_delayed_ref_root *delayed_refs;
 587         int count_mod = 1;
 588         int must_insert_reserved = 0;
 589
 590         /*
 591          * the head node stores the sum of all the mods, so dropping a ref
 592          * should drop the sum in the head node by one.
 593          */
 594         if (action == BTRFS_UPDATE_DELAYED_HEAD)
 595                 count_mod = 0;
 596         else if (action == BTRFS_DROP_DELAYED_REF)
 597                 count_mod = -1;
 598
 599         /*
 600          * BTRFS_ADD_DELAYED_EXTENT means that we need to update
 601          * the reserved accounting when the extent is finally added, or
 602          * if a later modification deletes the delayed ref without ever
 603          * inserting the extent into the extent allocation tree.
 604          * ref->must_insert_reserved is the flag used to record
 605          * that accounting mods are required.
 606          *
 607          * Once we record must_insert_reserved, switch the action to
 608          * BTRFS_ADD_DELAYED_REF because other special casing is not required.
 609          */
 610         if (action == BTRFS_ADD_DELAYED_EXTENT)
 611                 must_insert_reserved = 1;
 612         else
 613                 must_insert_reserved = 0;
 614
 615         delayed_refs = &trans->transaction->delayed_refs;
 616
 617         /* first set the basic ref node struct up */
 618         atomic_set(&ref->refs, 1);
 619         ref->bytenr = bytenr;
 620         ref->num_bytes = num_bytes;
 621         ref->ref_mod = count_mod;
 622         ref->type  = 0;
 623         ref->action  = 0;
 624         ref->is_head = 1;
 625         ref->in_tree = 1;
 626         ref->seq = 0;
 627
 628         head_ref = btrfs_delayed_node_to_head(ref);
 629         head_ref->must_insert_reserved = must_insert_reserved;
 630         head_ref->is_data = is_data;
 631
 632         INIT_LIST_HEAD(&head_ref->cluster);
 633         mutex_init(&head_ref->mutex);
 634
 635         trace_add_delayed_ref_head(ref, head_ref, action);
 636
 637         existing = tree_insert(&delayed_refs->root, &ref->rb_node);
 638
 639         if (existing) {
 640                 update_existing_head_ref(existing, ref);
 641                 /*
 642                  * we've updated the existing ref, free the newly
 643                  * allocated ref
 644                  */
 645                 kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
 646         } else {
 647                 htree_insert(&delayed_refs->href_root, &head_ref->href_node);
 648                 delayed_refs->num_heads++;
 649                 delayed_refs->num_heads_ready++;
 650                 delayed_refs->num_entries++;
 651                 trans->delayed_ref_updates++;
 652         }
 653 }
 654
 655 /*
 656  * helper to insert a delayed tree ref into the rbtree.
 657  */
 658 static noinline void add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 659                                          struct btrfs_trans_handle *trans,
 660                                          struct btrfs_delayed_ref_node *ref,
 661                                          u64 bytenr, u64 num_bytes, u64 parent,
 662                                          u64 ref_root, int level, int action,
 663                                          int for_cow)
 664 {
 665         struct btrfs_delayed_ref_node *existing;
 666         struct btrfs_delayed_tree_ref *full_ref;
 667         struct btrfs_delayed_ref_root *delayed_refs;
 668         u64 seq = 0;
 669
 670         if (action == BTRFS_ADD_DELAYED_EXTENT)
 671                 action = BTRFS_ADD_DELAYED_REF;
 672
 673         delayed_refs = &trans->transaction->delayed_refs;
 674
 675         /* first set the basic ref node struct up */
 676         atomic_set(&ref->refs, 1);
 677         ref->bytenr = bytenr;
 678         ref->num_bytes = num_bytes;
 679         ref->ref_mod = 1;
 680         ref->action = action;
 681         ref->is_head = 0;
 682         ref->in_tree = 1;
 683
 684         if (need_ref_seq(for_cow, ref_root))
 685                 seq = btrfs_get_tree_mod_seq(fs_info, &trans->delayed_ref_elem);
 686         ref->seq = seq;
 687
 688         full_ref = btrfs_delayed_node_to_tree_ref(ref);
 689         full_ref->parent = parent;
 690         full_ref->root = ref_root;
 691         if (parent)
 692                 ref->type = BTRFS_SHARED_BLOCK_REF_KEY;
 693         else
 694                 ref->type = BTRFS_TREE_BLOCK_REF_KEY;
 695         full_ref->level = level;
 696
 697         trace_add_delayed_tree_ref(ref, full_ref, action);
 698
 699         existing = tree_insert(&delayed_refs->root, &ref->rb_node);
 700
 701         if (existing) {
 702                 update_existing_ref(trans, delayed_refs, existing, ref);
 703                 /*
 704                  * we've updated the existing ref, free the newly
 705                  * allocated ref
 706                  */
 707                 kmem_cache_free(btrfs_delayed_tree_ref_cachep, full_ref);
 708         } else {
 709                 delayed_refs->num_entries++;
 710                 trans->delayed_ref_updates++;
 711         }
 712 }
 713
 714 /*
 715  * helper to insert a delayed data ref into the rbtree.
 716  */
 717 static noinline void add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 718                                          struct btrfs_trans_handle *trans,
 719                                          struct btrfs_delayed_ref_node *ref,
 720                                          u64 bytenr, u64 num_bytes, u64 parent,
 721                                          u64 ref_root, u64 owner, u64 offset,
 722                                          int action, int for_cow)
 723 {
 724         struct btrfs_delayed_ref_node *existing;
 725         struct btrfs_delayed_data_ref *full_ref;
 726         struct btrfs_delayed_ref_root *delayed_refs;
 727         u64 seq = 0;
 728
 729         if (action == BTRFS_ADD_DELAYED_EXTENT)
 730                 action = BTRFS_ADD_DELAYED_REF;
 731
 732         delayed_refs = &trans->transaction->delayed_refs;
 733
 734         /* first set the basic ref node struct up */
 735         atomic_set(&ref->refs, 1);
 736         ref->bytenr = bytenr;
 737         ref->num_bytes = num_bytes;
 738         ref->ref_mod = 1;
 739         ref->action = action;
 740         ref->is_head = 0;
 741         ref->in_tree = 1;
 742
 743         if (need_ref_seq(for_cow, ref_root))
 744                 seq = btrfs_get_tree_mod_seq(fs_info, &trans->delayed_ref_elem);
 745         ref->seq = seq;
 746
 747         full_ref = btrfs_delayed_node_to_data_ref(ref);
 748         full_ref->parent = parent;
 749         full_ref->root = ref_root;
 750         if (parent)
 751                 ref->type = BTRFS_SHARED_DATA_REF_KEY;
 752         else
 753                 ref->type = BTRFS_EXTENT_DATA_REF_KEY;
 754
 755         full_ref->objectid = owner;
 756         full_ref->offset = offset;
 757
 758         trace_add_delayed_data_ref(ref, full_ref, action);
 759
 760         existing = tree_insert(&delayed_refs->root, &ref->rb_node);
 761
 762         if (existing) {
 763                 update_existing_ref(trans, delayed_refs, existing, ref);
 764                 /*
 765                  * we've updated the existing ref, free the newly
 766                  * allocated ref
 767                  */
 768                 kmem_cache_free(btrfs_delayed_data_ref_cachep, full_ref);
 769         } else {
 770                 delayed_refs->num_entries++;
 771                 trans->delayed_ref_updates++;
 772         }
 773 }
 774
 775 /*
 776  * add a delayed tree ref.  This does all of the accounting required
 777  * to make sure the delayed ref is eventually processed before this
 778  * transaction commits.
 779  */
 780 int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 781                                struct btrfs_trans_handle *trans,
 782                                u64 bytenr, u64 num_bytes, u64 parent,
 783                                u64 ref_root,  int level, int action,
 784                                struct btrfs_delayed_extent_op *extent_op,
 785                                int for_cow)
 786 {
 787         struct btrfs_delayed_tree_ref *ref;
 788         struct btrfs_delayed_ref_head *head_ref;
 789         struct btrfs_delayed_ref_root *delayed_refs;
 790
 791         BUG_ON(extent_op && extent_op->is_data);
 792         ref = kmem_cache_alloc(btrfs_delayed_tree_ref_cachep, GFP_NOFS);
 793         if (!ref)
 794                 return -ENOMEM;
 795
 796         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 797         if (!head_ref) {
 798                 kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
 799                 return -ENOMEM;
 800         }
 801
 802         head_ref->extent_op = extent_op;
 803
 804         delayed_refs = &trans->transaction->delayed_refs;
 805         spin_lock(&delayed_refs->lock);
 806
 807         /*
 808          * insert both the head node and the new ref without dropping
 809          * the spin lock
 810          */
 811         add_delayed_ref_head(fs_info, trans, &head_ref->node, bytenr,
 812                                    num_bytes, action, 0);
 813
 814         add_delayed_tree_ref(fs_info, trans, &ref->node, bytenr,
 815                                    num_bytes, parent, ref_root, level, action,
 816                                    for_cow);
 817         spin_unlock(&delayed_refs->lock);
 818         if (need_ref_seq(for_cow, ref_root))
 819                 btrfs_qgroup_record_ref(trans, &ref->node, extent_op);
 820
 821         return 0;
 822 }
 823
 824 /*
 825  * add a delayed data ref. it's similar to btrfs_add_delayed_tree_ref.
 826  */
 827 int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 828                                struct btrfs_trans_handle *trans,
 829                                u64 bytenr, u64 num_bytes,
 830                                u64 parent, u64 ref_root,
 831                                u64 owner, u64 offset, int action,
 832                                struct btrfs_delayed_extent_op *extent_op,
 833                                int for_cow)
 834 {
 835         struct btrfs_delayed_data_ref *ref;
 836         struct btrfs_delayed_ref_head *head_ref;
 837         struct btrfs_delayed_ref_root *delayed_refs;
 838
 839         BUG_ON(extent_op && !extent_op->is_data);
 840         ref = kmem_cache_alloc(btrfs_delayed_data_ref_cachep, GFP_NOFS);
 841         if (!ref)
 842                 return -ENOMEM;
 843
 844         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 845         if (!head_ref) {
 846                 kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
 847                 return -ENOMEM;
 848         }
 849
 850         head_ref->extent_op = extent_op;
 851
 852         delayed_refs = &trans->transaction->delayed_refs;
 853         spin_lock(&delayed_refs->lock);
 854
 855         /*
 856          * insert both the head node and the new ref without dropping
 857          * the spin lock
 858          */
 859         add_delayed_ref_head(fs_info, trans, &head_ref->node, bytenr,
 860                                    num_bytes, action, 1);
 861
 862         add_delayed_data_ref(fs_info, trans, &ref->node, bytenr,
 863                                    num_bytes, parent, ref_root, owner, offset,
 864                                    action, for_cow);
 865         spin_unlock(&delayed_refs->lock);
 866         if (need_ref_seq(for_cow, ref_root))
 867                 btrfs_qgroup_record_ref(trans, &ref->node, extent_op);
 868
 869         return 0;
 870 }
 871
 872 int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
 873                                 struct btrfs_trans_handle *trans,
 874                                 u64 bytenr, u64 num_bytes,
 875                                 struct btrfs_delayed_extent_op *extent_op)
 876 {
 877         struct btrfs_delayed_ref_head *head_ref;
 878         struct btrfs_delayed_ref_root *delayed_refs;
 879
 880         head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
 881         if (!head_ref)
 882                 return -ENOMEM;
 883
 884         head_ref->extent_op = extent_op;
 885
 886         delayed_refs = &trans->transaction->delayed_refs;
 887         spin_lock(&delayed_refs->lock);
 888
 889         add_delayed_ref_head(fs_info, trans, &head_ref->node, bytenr,
 890                                    num_bytes, BTRFS_UPDATE_DELAYED_HEAD,
 891                                    extent_op->is_data);
 892
 893         spin_unlock(&delayed_refs->lock);
 894         return 0;
 895 }
 896
 897 /*
 898  * this does a simple search for the head node for a given extent.
 899  * It must be called with the delayed ref spinlock held, and it returns
 900  * the head node if any where found, or NULL if not.
 901  */
 902 struct btrfs_delayed_ref_head *
 903 btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr)
 904 {
 905         struct btrfs_delayed_ref_root *delayed_refs;
 906
 907         delayed_refs = &trans->transaction->delayed_refs;
 908         return find_ref_head(&delayed_refs->href_root, bytenr, NULL, 0);
 909 }
 910
 911 void btrfs_delayed_ref_exit(void)
 912 {
 913         if (btrfs_delayed_ref_head_cachep)
 914                 kmem_cache_destroy(btrfs_delayed_ref_head_cachep);
 915         if (btrfs_delayed_tree_ref_cachep)
 916                 kmem_cache_destroy(btrfs_delayed_tree_ref_cachep);
 917         if (btrfs_delayed_data_ref_cachep)
 918                 kmem_cache_destroy(btrfs_delayed_data_ref_cachep);
 919         if (btrfs_delayed_extent_op_cachep)
 920                 kmem_cache_destroy(btrfs_delayed_extent_op_cachep);
 921 }
 922
 923 int btrfs_delayed_ref_init(void)
 924 {
 925         btrfs_delayed_ref_head_cachep = kmem_cache_create(
 926                                 "btrfs_delayed_ref_head",
 927                                 sizeof(struct btrfs_delayed_ref_head), 0,
 928                                 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
 929         if (!btrfs_delayed_ref_head_cachep)
 930                 goto fail;
 931
 932         btrfs_delayed_tree_ref_cachep = kmem_cache_create(
 933                                 "btrfs_delayed_tree_ref",
 934                                 sizeof(struct btrfs_delayed_tree_ref), 0,
 935                                 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
 936         if (!btrfs_delayed_tree_ref_cachep)
 937                 goto fail;
 938
 939         btrfs_delayed_data_ref_cachep = kmem_cache_create(
 940                                 "btrfs_delayed_data_ref",
 941                                 sizeof(struct btrfs_delayed_data_ref), 0,
 942                                 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
 943         if (!btrfs_delayed_data_ref_cachep)
 944                 goto fail;
 945
 946         btrfs_delayed_extent_op_cachep = kmem_cache_create(
 947                                 "btrfs_delayed_extent_op",
 948                                 sizeof(struct btrfs_delayed_extent_op), 0,
 949                                 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
 950         if (!btrfs_delayed_extent_op_cachep)
 951                 goto fail;
 952
 953         return 0;
 954 fail:
 955         btrfs_delayed_ref_exit();
 956         return -ENOMEM;
 957 }